Recent heavy rains favor fungal spore production and development of diseases such as tan spot, septoria leaf blotch and leaf rust.
Fusarium head blight is also a looming threat but the decision to spray a fungicide depends on the condition of the individual field.
For example, a waterlogged field with standing water or crops flatted by wind and rain might not be good candidates.
Winter wheat that has already flowered may be beyond the help of a fungicide.
The best candidates are spring wheat crops with high yield potential.
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An application of Tilt at the flag leaf to head-out stage may be warranted if there is evidence of leaf diseases on about 25 percent of the area of the lower leaves, and if there are some yellow spots on upper leaves.
Growers may consider waiting a few days to the full heading stage and scout fields again if there is only a low level of leaf disease at the flag leaf stage.
The options at that time are applying Dithane or waiting until the early flowering stage and applying Folicur or Bravo.
Manitoba research indicates the best time to apply fungicide for fusarium head blight control in wheat and durum is at early flowering, which means that 25 percent of the main stems are flowering, while tillers have not started yet.
Fungicide applications under severe disease pressure usually give an average of 10 to 15 percent yield increase and may result in a better grade.
